The official WB2 website now has pictures of the cast if you'd like to see them:
http://www.fujitv.co.jp/waterboys2/cast_mm.html
The girls in this one are really cute.
There may be errors in the romanized names of the cast, I apologize for any mistakes.
(Especially true of the Waterboys section: Should only be used as a rough guide to the cast/chara names)
MAIN CAST
Ichihara Hayato / Mizushima Eikichi
Nakao Akiyoshi / Yamamoto Yousuke
Saito Keita / Kawasaki Senichi
Koike Teppei / Iwata Iwao
Kimura Ryo / Hideki Sano
SUPPORTING CAST
Ishihara Satomi / Yazawa Shiori
Kaneko Takatoshi / Saotome Hijiri
Yamaguchi Sayaka / Ohara Natsuko
Asami Reina / Kayo Oba
Inoue Waka / Koshino Haruka
Suzuki Emi / Kitagawa Kozue
Kimura Midoriko / Kashiyama Reiko
Imafuku Masashiosu / Mizushima Kamekichi
Yajima Kenichi / Mizushima Eitarou
Kohinata Fumiyo / Yazawa Mei
Morishita Aiko / Yazawa Kaoru
Sano Shiro / Kasuya Kozo
Kakuda Takuya / Tatsuya
Kakuda Kazuya / Kazuya
Asakura Erika / Utae
Nakahodo Hitomi / Terue
WATERBOYS
Abe Ryohei / Taizo
Yamane Kuzuma / Hiramasa
Takafumi Shinohara / Kanpachicho
Uchida Yuusuke / Uchimura
Sakata Tomoyasu / Sakagami
Teguchi Tetsuya / Hamaguchi
Yokotani Hidetoshi / Tanisaka
Ichikawa Gonmare / Shimura
Zen Ryou / Takei
Nagamachi Taro / Choutaro
Touo Tsubasa / Osaki
Nagai Masahiro / Suenaga
Yagishita Yousuke / Ueyanagi
Saito Makoto / Saijou
Sato Tadasuke / Katou
Fujinuma Yutaka / Numata
Yokogami Takuya / Yokoyama
Watanabe Kou / Tanabe
Kobayashi Daisuke / Komori
Shibuya Kento / Shibukawa
Hashimoto Atsushi / Hashino
Tagami Naoki / Kawakami
Takahashi Ryosuke / Niinuma
Takaguchi Yukihiro / Toba
Kuno Hidetaka / Itsuki
Hisamitsu Kunihiki / Kitajima
Mazawa Ketsu / Hikawa